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<html lang="zh-cn">
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        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
        <title>Document</title>
        <style>
            *{
                padding: 0;
                margin: 0;
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            html,body{
                height: 100%;
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            .box{
                height: 100%;
                width: 100%;
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                display: -webkit-flex;
                display: -moz-flex;
                display: -ms-flex;
                display: -o-flex;
                display: flex;
            }
            .f1{
                flex:1;
            }
            .bg-red{
                background-color: #f00;
            }
            .bg-green{
                background-color: #0f0;
            }
            .bg-blue{
                background-color: #00f;
            }
            .h-100p{
                height: 100%;
            }
            .box-100p-80{
                width: 100%;
                height: 80px;
            }
            .poa{
                position: absolute;
            }
            .b0{
                bottom: 0;
            }
        </style>
        <script>
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    </head>
    <body>
        <div style="display: flex; height: 100%; flex: 1 1 0%; background-color: red">
            <div style="display: flex;  flex: 1 1 0%;height: 400px; background-color: yellow"></div>
            <!-- <div style="display: flex; flex-direction: column; flex: 1 1 0%;">
                <div style="position: relative; overflow: auto; display: flex; flex: 1 1 0%; order: 0; background-color: green; height: 704.125px;">
                    <div style="display:flex;width: 100%;height:1400px;background-color: blue;"></div>
                </div>
                <div style="display: flex;
                    flex-direction: row;
                    align-items: center;
                    height: .88rem;
                    color: #333;
                    background-color: #edeef1;
                    position: relative;
                    order:1"></div>
            </div> -->
        </div>
        h2{填充整列：加flex-direction: column;}
        <div style="display: flex; height: 100%; flex: 1 1 0%;flex-direction: column; background-color: red">
            <div style="display: flex;  flex: 1 1 0%;height: 400px; background-color: yellow"></div>
        </div>
    </body>
</html>